This entrée is low in calories, high in nutrition, and packed with flavor and texture surprises. The Japanese most often serve this dish with assorted pickled vegetables and a miso-thickened soup. A large tossed green salad completes this meal just as nicely.
Slice the fillet in half lengthwise. Combine the rice wine and salt in a flat dish, and marinate the fish in the mixture while cooking the noodles.
Bring a large pot of water to a rolling boil. Add the buckwheat noodles and cook for 5 minutes once the water has returned to a boil. The noodles will still be firm. Drain, and rinse the noodles under cold water to remove excess starch and to stop the cooking. Drain again.
Remove one of the pieces of fish fillet from the marinade and lay it, smooth side down, on a cutting board. Lay half the noodles across the center of the fish. Roll the fish over the noodles to enclose them. Place this packet, seam side down, in a steamproof or microwave-safe shallow bowl or deeply rimmed dish. (Broad, shallow soup bowls are often a good choice.) Repeat the rolling process with the remaining fillet of fish and noodles; place this packet on a separate dish.
You can either steam the fish or use a microwave oven to cook this dish; the latter is faster and yields prettier results without compromising on flavor.
For the microwave: Cover the dishes snugly with clear plastic wrap, then poke several holes in the wrap to vent steam as the fish cooks. Cook the noodle-stuffed fish for 2 minutes on high setting (100 percent power or 600 watts). Remove the dishes from the oven and pour off any liquid that may have accumulated. Divide the Smoky Sea Stock between the two dishes and pour it over the noodle-stuffed fish. Cover the dishes again, poke several holes to vent steam, and cook for another 40 seconds on high.
To steam: Bring the water in the bottom of a large steamer to a rolling boil over high heat. Lower the heat to allow for a steady flow of steam and cook the fish, covered, for 3 minutes. Carefully remove the lid from your steamer, and use paper towels to blot up any excess liquid that has accumulated in the bowls or dishes. Divide the Smoky Sea Stock between the two portions, and pour it over the fish. Cover the steamer again and cook for 2 minutes. Remove the steamer from the heat, and let the fish “settle” for another 2-3 minutes. Use pot holders to carefully remove the very hot dishes from the steamer.
Place a mound of grated radish, a mound of grated ginger, and a mound of chopped green scallions on top of each portion of fish. Serve immediately. Each diner takes these condiments and swishes them in the pool of sauce surrounding the fish.